Photo Illustration by The Daily Beast

ROME—When art experts from 44 countries and 13 non-governmental organizations gathered in Washington, D.C. in December 1989, they had one goal in mind: to finally return half a million pieces of art stolen from Jewish people by the Nazis during World War II.

American diplomat Stuart Eizenstat spearheaded the writing of an 11-point document called the “Washington Principles on Nazi-Confiscated Art” that, had it worked, would have seen a global release of around 600,000 pieces of art held by governments, museums and private collectors back to the families of prominent Jewish art collectors of the early 20th centuries to whom it belonged.

Instead, 20 years later, the group is meeting in Berlin, hosted by the German Lost Art Foundation, to measure the progress—and it isn't all good.

Eizenstat, who is attending the conference this week, said that five countries in particular that have the most looted art have done the worst job with righting the wrongs of history. He pointed to Spain, Italy, Russia, Hungary and Poland as the countries that are holding back progress. “We must candidly confront the unfulfilled promises we solemnly made,” he said in opening remarks.

Hungary and Poland, he said, have been “repeatedly asked” to restitute art known to belong to Jewish Holocaust survivors. Italy instead seems more concerned with retrieving national treasures that were looted and sold to American museums.

Spain, he said, has taken “no steps” at all towards returning art proven to belong to Jewish descendants. He said Russia lacks even the means to process claims by families who know their stolen ancestral art was taken from the Germans to Russia at the end of World War II.

On a rare positive note in his remarks, Eizenstat did laud Austria, Holland and Germany for their compliance, though not complete, in returning tens of thousands of pieces known to have been stolen.

Arthur Brand, a leading art detective who has earned the nickname of the “Indiana Jones” of looted art, said that it was surprising the lengths those in possession of the art go to to keep it.

As reported by Artsy, Brand most recently returned a 1,600-year-old mosaic to its rightful owners in Cyprus, but he is perhaps best known for finding two bronze statues called Hitler's Horses and around $6 million worth of Nazi-looted art in 2015.

He told The Daily Beast that countries and museums that cling on to stolen art use the very “Nazi tactics” the Nazis themselves used to steal it in the first place.

In many cases if families were incarcerated in concentration camps, their archives and provenance records were destroyed and replaced by counterfeit provenance documents or fake bills of sale. Other times Nazis fabricated tax debts that were marked paid by the acquisition of their art.

Brand said that many museums now use those old Nazi records as proof that the Jewish families “sold” their art and, as such, the provenance is legitimate.

“The Germans started stealing from Jews in 1933,” he said. “They wanted to sell many of these pieces on auctions to get money for the German state, but they could not say they were stolen on an auction bill, so what did the Germans do? They made it appear legitimate. Jewish collectors and art dealers were given an invented tax penalty bills, and in order to pay them they had to give up the paintings.”

Brand said that museums often use the old Nazi records as “proof” the paintings were legitimately sold. “Even today many countries and many museums use the Nazi tactics and hope that they can prolong it until these people die or they have forgotten,” he said.

Statutes of limitations have also hindered the process in claiming, investigating and recovering art that rightfully belongs to Jewish survivors.

In 2008, on the 10th anniversary of the Washington Principles document, many countries relaxed statute of limitations regulations to allow Jewish families to investigate and make claims on their stolen art works.

“It sounds reasonable that they should return the art, but these descendants and Jewish survivors did not have a chance to make claims,” Brand said. “Between 1945 and 2008, when they went to a museum or government they were told, 'Look you survived the war, get out of here.'”

One way to determine if a museum is cooperative or complicit is whether they offer an online database called Provenance Research Project, listing objects with questionable provenance obtained during and after World War II.

Those that do, like the Met and Guggenheim, invite potential heirs to look through lists. Some countries have set up panels that will rule on disputed art claims based on testimonies, records and whether or not the only proof of sale is the Nazi-produced documentation.

Some private collector estates, like Max Stern, have their own database of missing art they hope to retrieve, though it usually takes detectives like Brand to put pressure, either through media attention or legal threats, to get them to give up the goods.

There are also ample success stories of families reunited with their works. Famously, Gustav Klimt's “Portrait of Adele Bloch-Bauer” was stolen by Nazis in 1941 and displayed at the Osterreichische Galerie Belvedere, until 2006 when the Bloch-Bauer family finally won it back. They promptly sold it for $135 million. The story is depicted in the best-selling book and movie, Woman in Gold.

Nicholas O'Donnell, attorney and author of A Tragic Fate: Law and Ethics in the Battle Over Nazi-Looted Art, is not sure conferences like the one in Berlin do much to call people to action.

“I think it is important to recognize the significance of the Washington Principles and the impact compared to before 1989, but its value is pretty limited,” he said. “It is hosted by the German government, which I've been critical off and litigated against, but more than that it seems backward-looking.”

He said that in some cases it truly is difficult to know what happened to the art between the time it was stolen and where it ends up. After the allies established military rule at the end of World War II, they instituted the so-called Military Zone Government Law 59 that essentially stated that any art sale that was acquired from Jewish or persecuted people during that time should be considered invalid.

Brand has worked with private collectors who bought stolen works unwittingly to make agreements with Holocaust survivors and heirs.

Because major auction houses like Christie's and Sotheby's will not list an item if there is a claim against it, he encourages them to work together. “Here the buyers are innocent, so they go to the Jewish family and work together to sell the pieces together and split the profits, he said.

“It's logical that a museum feels pain when it has to give an important piece back,” he said. “But these people were murdered or everything was stolen, and at the end of the day it does not belong to the museums, it belongs to the families. That's the true provenance.”

O'Donnell, who has tried cases all over the world to try to get stolen art back to its rightful owners, said that he has found many people choose to ignore the circumstances under which the art was acquired.

“Often, buyers do end up with art they bought in good faith. But not everyone comes to this issue in good faith,” he said. “The ethical discussion remains very important. Some people are receptive to ethical pressure and some people are not. In that latter category.”

Much of the art O'Donnell tries to get back isn't even particularly valuable on a financial scale, which he finds even more frustrating. “It's not always about the value of the object,” he said. “It's often just about the principle. Although the generation of actual survivors is dwindling, a younger generation is engaged with the question and that's important.”